DETROIT--If plug-in electric cars become popular in your neighborhood, you may face an electricity supply crunch when it comes to charging.
There have been a number of studies measuring whether the national power grid can fuel large numbers of electric vehicles. But the biggest concern regarding the impact of plug-ins is at the local level, where adding just a few vehicles could strain a local circuit, said Peter Darbee, the CEO of California utility Pacific Gas & Electric, during a talk at the Business of Plugging conference here Tuesday.
Darbee predicts that demand for plug-in vehicles will be very high, as turned out to be the case with cell phones. Based on early data, it's clear that purchasers of plug-in electric vehicles live near each other. Berkeley, California, for example, represents 18 percent of all customers in PG&E's territory while Fresno is only 2 percent.
PG&E CEO Peter Darbee; John Lauckner, General Motors' vice president of global program management; and George Pataki, former New York governor and counsel at Chadbourne & Parke, on a panel at the Business of Plugging In conference in Detroit.
(Credit: Martin LaMonica/CNET)But high concentrations of plug-in electric vehicles poses a serious challenge to utilities, Darbee said. Plug-in electric cars could draw electricity equivalent the amount needed to run one home, or up to three homes in certain places, he said.
"You can see if you have three or five electric cars arrive in a neighborhood, you're going to overload the local circuits, and that will lead to blackouts," Darbee said. "So we see it as an opportunity but we also see it as a challenge of significant proportions."
Darbee said that utilities need to work with auto companies and policy makers to ensure that customers have a smooth experience and that the grid is not stressed.The utility--considered one of the most progressive in the U.S.--is also taking a number of steps to avoid potential problems.
PG&E plans to recommend that consumers have a 220-volt charging point at home, which will allow most plug-in electric cars to recharge in two or three hours, rather than six or seven hours for a regular 110-volt outlet. Although it's more convenient for consumers, that higher-voltage charging significantly boosts the draw--as much as 6.6 kilowatts.
Darbee said that PG&E is a strong endorser of plug-in electric vehicle technology because it can significantly reduce carbon dioxide emissions and reduce imports of foreign oil. But there is a "nightmare" scenario for utilities. That's when large numbers drivers come home on a hot day when the load is already maxed out and they turn on air conditioners and lights, and plug in their cars.
"If that (charging) were at 220 (volts), the results would be pretty dramatic and pretty negative. You would create a peak on top of the current peak load. The effect would be to bring down the electrical system if you had substantial concentrations in the area," Darbee said.
To avoid that situation, PG&E plans to offer a 220-volt charger along with a timer. The consumer would be able to get off-peak rates--called dynamic pricing--by charging between 11:00 p.m. and 4:00 a.m.
Smart-grid technology, whereby homes are equipped with meters that can communicate with the utility, gives more flexibility. In that case, the utility could charge three electric cars in succession or at different rates overnight to ease the draw on a local circuit. Or the utility could offer consumers a menu of charging alternatives.
In about seven or 10 years, utilities are envisioning vehicle-to-grid capability in which a plug-in electric car owner would sell electricity from a battery back to the grid. A driver could program the system so that the stored energy is sold only at a certain price, Darbee said.
The costs of bulking up local electricity circuits should be shared by all people in a service territory, he argued. "Just like when there were hair dryers or electric driers, there was a shared cost," he said.
Pacific Gas & Electric is going to great lengths--all the way to space--in its quest for renewable energy.
The California utility on Monday said that it will seek approval from regulators to purchase 200 megawatts worth of solar energy delivered from stealth space solar power company Solaren over 15 years.
(Credit:
Space Energy)
The idea of space-based solar power (SBSP) is to place a device in space that can convert solar energy into a usable form and have it transmitted wirelessly to Earth. Scientists have thought to capture solar energy from space for decades but has it has never been done commercially.
Solaren proposes placing solar panels on a satellite to generate electricity that is converted to radio frequency energy on-board and sent to a ground station in California. The receiver then converts the radio frequency energy to electricity and it is fed into the power grid.
The goal of the project is to provide electricity to PG&E by 2016, said Solaren CEO Gary Spirnak in a Q and A posted on PG&E's company blog.
"While a system of this scale and exact configuration has not been built, the underlying technology is very mature and is based on communications satellite technology. For over 45 years, satellites have collected solar energy in earth orbit via solar cells, and converted it to radio frequency energy for transmissions to earth receive stations. This is the same energy conversion process Solaren uses for its (space solar power) plant," he said.
PG&E, which has significant investments in different forms of renewable energy, said that there is no risk to the utility since it only pays for power produced.
The advantage of space solar power is that energy can be harnessed at all times, even at night or when it's cloudy. Solaren's contract calls for it to deliver baseload power, the electricity needed to meet customer demand.
In its posting, PG&E executives said that generating space solar power cost effectively is a major challenge, but the people at Solaren have a lot of experience in space and satellites. The field also can also draw on years of research.
Another company called Space Energy has been formed to also tap solar energy from space using a similar technique as Solaren.
Californians' love for electronic gear takes a heavy toll on electricity bills, sucking up 20 percent of total power consumption.
Utilities Pacific Gas & Electric (PG&E) and Sacramento Municipal Utility District (SMUD) on Thursday announced a program to steer consumers toward more energy-efficient electronics.
Called the Business and Consumer Alliance, the program will identify which TVs, desktop computers, and monitors are the most energy efficient based on industry standards, such as EnergyStar.
Merchandise in stores will be labeled with either a "Save" or a "Save More" label to highlight energy-efficient equipment, said a representative from PG&E, which is dedicating $7 million this year to the program.
Best Buy, Sears Holding Company, Wal-Mart, Sam's Club, Dell, and Lenovo are participating in the program which the utilities estimate will save 380 million kilowatt-hours (kWh) of electricity through 2011. That's enough to power more than 55,000 typical homes.
The hope is to drive demand for efficient consumer electronics at the retail level, which could prompt manufacturers to invest in energy-efficient improvements.
PG&E anticipates that the program will have more money dedicated to it in the coming years and cover more categories of products.
Right now, the biggest energy consumers are flat-screen TVs and small-office equipment. But set-top boxes and electronics chargers are quickly becoming bigger factors in residential electricity use, the PG&E representative said.
Energy consumption from consumer electronics is expected to grow at close to 11 percent annually from 2005 to 2010.
NEW YORK--California utility Pacific Gas & Electric is betting big on solar power but it's still not sure which technology will ultimately win out.
PG&E's senior vice president of energy procurement, Fong Wan, on Tuesday said that the utility has opened up bidding for a 2-megawatt solar photovoltaic array, part of a five-year program to install 500 megawatts worth of solar power in California, one of the biggest programs in the country.
Solar photovoltaic panels with trackers at the Nellis Air Force base in Nevada.
(Credit: SunPower)Wan spoke at the Jefferies Global Clean Technology Conference here about the utility's renewable energy and efficiency strategy, offering insights into the hurdles and real-world tradeoffs of using different green technologies.
In addition to its huge solar program, the company--considered one of the most progressive and technology-savvy utilities in the U.S.--is in the process of rolling out smart-grid capabilities to 5 million homes. It is also exploring large-scale energy storage methods, including batteries, compressed air, and pumped hydro, executives said.
Its investments in solar are driven by state mandates that require utilities to get 20 percent of their electricity from renewable sources by 2010, which could be increased to 33 percent by 2020.
PG&E recently decided to install solar power facilities itself because it has the capital and income to take advantage of a federal 30 percent tax credit for renewable energy investments. The lack of profits at many banks has dried up the market for renewable energy investments that rely on tax credits.
The utility will install about 250 megawatts worth of solar power facilities itself and purchase the rest from independent power producers. Each installation will be medium-size--between 2 and 20 megawatts. Two megawatts of capacity would be enough to supply about 600 homes.
PV or CSP?
The first 2-megawatt project will be a solar photovoltaic (PV) installation near a PG&E substation. But the utility is also investing in concentrating solar power (CSP) systems, which create heat from the sun to make steam that turns an electricity turbine, Wan said. There are a number of CSP designs, including mirrored troughs and flat mirrors to reflect light to make heat.
The cost for both solar PV and concentrating solar power continues to go down, but it's not clear yet which one will be most economic for the utility in the long run, he said.
"It's going to be a really, really interesting and close race. No one knows the answer as to who is going to win. We're interested in building a portfolio of both," Wan said.
Each offers different advantages and is better suited for different environments. Concentrating solar power systems are more efficient overall, but they require water cooling to get the highest levels of efficiency, Wan said. CSP systems, which can be large 500 megawatt-installations, offer cost efficiencies through scale and have some storage options.
PV panels, on the other hand, are well-proven technology and can be installed in smaller increments and connected to the grid without massive transmission upgrades. That siting flexibility, even if costs are higher, is a significant advantage to solar PV panels, said Wan.
"PVs are easier to implement right off the bat. CSPs are dependent on transmission," he said. "CSP (systems) are all in the desert and there's no existing transmission lines that will go there. A generation plant is hard enough to site, but a transmission line would impact a whole path of probably 100 communities."
By investing in solar, PG&E is hoping to accelerate cost reductions by fostering competition between different PV and CSP technologies, he said.
Storage, too, is a technology where PG&E is a leading-edge customer.
Having several hours of storage available allows utilities to flatten out their power generation over the course of a day. The peak electricity demand at PG&E late in the afternoon can be double its power generation during the middle of the night. That means some power plants are only used 40 times a year, said Wan.
The company is investigating the use of lithium-ion batteries for storage as well as so-called flow battery where giant tanks hold electrolytes that are released to create a few hours' worth of electricity.
For the last 20 years, PG&E has had a pumped hydro station where water from a reservoir is pumped up to the top of a mountain and then released to make electricity during off-peak times. The utility is exploring three more sites.
With compressed air storage, pressurized air is pumped into underground formations such as limestone caverns. PG&E is working with the Electric Power Research Institute to evaluate suitable sites, said Hal La Flash, PG&E's chief technology officer.
PG&E's smart-grid program envisions using communications technology to better control the flow of electricity across a more diverse grid of centralized and distributed power generation.
(Credit: Martin LaMonica/CNET)The company's smart-grid program of equipping 5 million homes with systems to let consumers take advantage of off-peak rates will be installed in the next two and a half years, according to Scott Lang, the CEO of Silver Spring Networks, the company which PG&E chose for the smart-grid roll-out. Lang also spoke at the Jefferies conference on Tuesday.
On average, smart-grid trials have shown that consumers can decrease energy consumption between 5 and 15 percent by having more information on usage. Through energy-efficiency programs, the per capita energy consumption of California residents has stayed steady since the 1970s.
See Martin LaMonica's microblogs/tweets from the Jefferies conference on Twitter.
California utility Pacific Gas & Electric on Tuesday announced a five-year program to produce 500 megawatts worth of solar energy from distributed solar panels.
Rather than build one giant solar power plant, PG&E plans to generate solar power from a collection of midsize projects, from 1 megawatt to 20 megawatts. This investment will cover half of the total target of power generation.
(Credit:
Martin LaMonica/CNET Networks)
One megawatt is enough to power one large retail store or roughly 300 homes. A large solar installation at a single business, such as Google's rooftop array and solar carport, can be over 1 megawatt in generating capacity.
Solar photovoltaic panels will be mounted on rooftops or mounted on poles in PG&E's service area in Northern and Central California. The utility will seek to install the panels on land it already owns or near substations to avoid having to build new transmission lines, it said.
PG&E will rely on outside providers for the other 250 megawatts. If operating by 2015, the electricity will be enough to power 150,000 homes annually and account for 1.3 percent of PG&E's electrical demand.
The move is one of the largest solar-power projects to date and significant because it represents the first time in more than 10 years that PG&E has invested directly in renewable energy. Until now, it typically purchased electricity from third-party clean-energy project developers.
Many project developers and financiers are unable to take advantage of the 30 percent renewable-energy tax credit because they don't anticipate having a tax bill. Because PG&E has a "tax appetite" and can take advantage of the tax credit, the utility is investing directly in solar energy, CEO Peter Darbee said last month when he first mentioned the solar project.
California has a renewable portfolio standard that mandates that utilities get 33 percent of their electricity from renewable sources by 2020. In the past month, two other large solar projects--one with NRG Energy and one with Southern California Edison--were announced.
Because the recently passed stimulus package now allows utilities to take advantage of the 30 percent tax credit, more utilities will build and own solar facilities, said Julia Hamm, the executive director of the Solar Electric Power Association, in a statement.
Environmental advocacy group Natural Resources Defense Council lauded the PG&E plan because building distributed solar power is a relatively quick way to deploy the technology.
"PG&E's intent for development of these projects--on already developed land close to transmission and distribution--is exactly where it needs to be to reduce environmental impacts and speed development," said Sheryl Carter, Energy Program co-director at the NRDC, in a statement.
PG&E said that it submitted the plan on Tuesday to the California Public Utilities Commission and that it could be approved later this year.
INDIAN WELLS, Calif.--Pacific Gas & Electric, one of the country's largest and most progressive utilities, will invest directly in solar power plants and solar panels distributed in different California communities.
CEO Peter Darbee said the move represents the first time that PG&E--already a large purchaser of solar and other renewable energy technologies--will build and own solar installations. Right now, the utility purchases clean energy from third parties.
Darbee mentioned the solar initiative during a discussion on Wednesday here at the Clean-tech Investor Summit.
Peter Darbee (left), the CEO of Pacific Gas & Electric is interviewed by venture capitalist Ira Ehrenpreis at Clean-tech Investor Summit.
(Credit: Martin LaMonica/CNET Networks)He declined to specify how much the investment would be but said that it would be "significant." After his talk, he acknowledged it would comparable in size to Southern California Edison's program to spend $850 million over five years to put solar panels on commercial rooftops.
California utilities are some of the most important purchasers of clean technologies and vital customers for a raft of energy technology developers. The state mandates that utilities get 33 percent of their electricity from renewable sources by 2020.
PG&E has already signed deals to purchase renewable energy from a handful of solar power start-ups. These companies, such as BrightSource and Ausra, build and own power plants, using solar panels or solar thermal technology. PG&E or other utilities purchase the electricity they generate.
But the financial environment and the structure of the solar subsidy has made building these solar facilities more tenuous.
"We will do a filing (with regulators) in the next quarter to make an equity investment in renewable energy," Darbee said. "We are going to move to an equity investment because we have a tax appetite whereas so many other entities do not."
Investors for renewable energy projects get a 30 percent tax credit but with corporate profits slipping, fewer companies are willing to put money into these deals.
Darbee said that the renewable energy investment will include central solar power plants as well as distributed solar projects in municipalities that want to push clean energy in their communities, such as the California county of Marin.
With distributed solar, PG&E could own and operate the panels installed on the rooftops of commercial buildings and homes. This sort of model, being pursued by Duke Energy and Southern California Edison as well, suits utilities well because the solar panels generate the most electricity during peak times of the day.
MENLO PARK, Calif.--Solar power hasn't swept the nation but it must and will, said members of utilities, clean-tech start-ups, venture capital firms, and academia at the Big Solar conference here Wednesday.
California will literally live up to its "Golden State" nickname and shine as a model for the rest of the country thanks to progressive lawmakers, Silicon Valley dealmakers, and innovators at state and university labs, according to the event's many optimists.
"The time has come in the United States for large-scale solar," said Ed Smeloff, senior manager of utility project sales at SunPower, a maker of solar systems including those at the nation's largest plant at Nellis Air Force Base in Nevada. "The wind is to our backs on this."
Among the bright points noted by Smeloff and others, each presidential candidate supports clean energy, of which solar is the best understood.
U.S. photovoltaics account for just 8 percent of the global market totaling 2,826 megawatts, according to a Solarbuzz report.
Demand for electricity will expand one-third by 2030, according to the Energy Information Administration. Solar producers hope their energy product will fill the gap with a minimal carbon footprint.
Even in California, however, conference attendees spoke of stunted growth in solar. To start, it's expensive. Laws meant to help the spread of solar and protect ecosystems may also hurt the sector, some argued. And financing plans and tax incentives designed to spur installation may bring unintended negative side effects.
Solar power is recognized as the most expensive form of energy at around 30 cents per kilowatt hour. By comparison, coal costs about 5 cents and natural gas 4 cents per kilowatt hour.
"We're looking for the biggest bang for the buck," Roy Kuga, vice president of Pacific Gas & Electric's energy supplies division, said at the event, which was held by UC Berkeley and Stanford University.
Silicon supply stunts growth
As 26 U.S. states including California are requiring some renewable energy in utilities' portfolios, more utilities are jumping on the solar bandwagon.
The limited availability of silicon has partly stalled the growth of the solar sector.
"We're struggling to provide one-third of what people want from us, and we're No. 1," according to Kristina Peterson, director of structured finance at solar module maker Suntech.
However, supplies could increase by 33 percent this year and 23 percent in 2009, according to research firm Gartner. From the world's modest 8 suppliers of silicon, 100 new providers could emerge by 2009, Peterson said.
No matter how renewables improve in efficiency and price, Kuga of PG&E said he foresees a continued reliance on the grid, especially for peak demand.
Renewables make up less than 3 percent of U.S. energy, according to the Department of Energy. They can be less reliable than tried-and-true yet carbon-intensive sources like coal. Both solar and wind depend upon the whims of weather.
Meanwhile, makers of solar systems are racing to enhance efficiency. Some look at silicon alternatives, copper indium gallium selenide (CIGS), or cadmium telluride. There's even more variety in the forms that solar systems take, from glass-and-metal panels to thin films built into windows to bobbing plastic balloons.
"It's hard to say who will succeed and who will not," Kuga said. "The guy with very little funding may have the home run technology."
Just as the mix of solar technologies continues to shift, the nation's future energy portfolio is likely to be extremely diverse.
The California Solar Initiative calls for 3,000 sun-powered megawatts by 2016. Under the California Renewables Portfolio Standard, electricity providers by 2010 must ramp up renewable sources to 20 percent of sales.
But with the federal renewable energy tax credit ending by January, many solar projects are on hold. The credits expired twice in previous years until Congress retroactively re-established them.
"It's pushed us into looking at programs in Canada and Europe," said Joseph Kastner, vice president of solar operations at MMA Renewable Ventures, which helps to finance clean-energy projects.
Legislative missteps
The West Coast, particularly California, is a stronghold for solar support from policymakers. At the same time, regional missteps are holding back solar development, according to some in the solar industry.
The Clean Energy Initiative on the California ballot this fall would require 50 percent of energy from renewables by 2050. But as it stands it would effectively kill the state's solar sector by disqualifying any project under 30 megawatts, warned Sue Kately, executive director of the California Solar Energy Industries Association.
A regulatory fast track should approve the ecological soundness of large-scale solar plants, said Marc Gottschalk, co-chair in the clean-tech practice of Wilson Sonsini Goodrich & Rosati.
Although solar panels don't create obvious hazards or polluting emissions, large installations may be left in limbo for six months to a year during a review by the California Environmental Quality Act, he explained. The National Environmental Policy Act can add more delays, said Gottschalk, also co-chair of the California Clean Tech Open.
For instance, OptiSolar plans to build the largest U.S. solar farm of 550 megawatts, but it must ensure the safety of endangered species from nearby Carrizo National Monument.
Connecting the many distributed systems to the grid is still a bridge to cross, some mentioned.
Punitive taxes are another barrier, according to Kastner of MMA Renewables, which has 27 megawatts of photovoltaics in 10 states, including the 14-megawatt plant at Nellis Air Force Base. In some cases, property taxes tripled after the solar panels went up, Kastner noted.
Kateley, on the other hand, warned that consumers must check the fine print within the terms of financing plans for solar installations. Residential customers, in particular, should understand they may get help with installation through leases and Power Purchase Agreements, but wouldn't own the panels on their buildings.
She also raised an eyebrow when addressing venture capitalists. "You're flushing a lot of money into these systems and some of you might be a little reckless," she said, adding that because the business world may favor "shiny" photovoltaics, more common-sense solutions such as solar thermal are being overlooked.
Solar may appear the "sexiest" slice of the clean-tech sector, but the number of solar companies has contracted slightly since last year. As the industry matures, the shades come on.
This post has been changed to reflect that the true nickname for California is the "Golden State," not the "Sunshine State." Thanks to the reader who pointed this out./i>
That ancient, inefficient heating/air conditioning system in your building might be worth something someday.
Pacific Gas & Electric CEO Pete Darbee said in a briefing with reporters Tuesday that the utility is working with government officials to see if there is a way to create a fund that gives building owners financial incentives to replace old compressors, pumps, and other building equipment with new, energy-efficient versions.
Building owners want to get rid of this old equipment, he explained, but the capital requirements are a big hurdle. The program could be structured in a way so that it could be funded partly through the utility bills paid by the customer.
The program would, in some sense, be similar to the residential energy rebate programs PG&E has run for years. Under those, PG&E gives cash rebates to homeowners who replace old washers and dryers with new ones. The utility has also underwritten programs to get consumers to replace incandescent bulbs with energy-efficient compact fluorescent bulbs.
Energy efficiency is the top priority in PG&E's effort to reduce greenhouse gas emissions. For one thing, energy conservation is less taxing on the environment than even getting more power from renewable sources of energy like solar panels.
Energy efficiency is also far cheaper. Technology for energy efficiency costs about 3 to 4 cents per kilowatt-hour, Darbee said. Harvesting energy from a renewable resource might cost 10 to 15 cents a kilowatt-hour or more. Rooftop solar panels have historically hovered around 40 cents a kilowatt-hour, he said. Energy efficiency standards implemented in California in the '70s also show that the programs work--energy consumption per capita has stayed relatively stable in the state since then but have risen substantially in other parts of the nation. Efficiency allowed California not to build 24 power plants in the last 35 years, he argued.
"The fact that you don't use power is the best strategy," he said.
Darbee, who has helped put PG&E at the forefront of greening utilities, spoke at length on a number of topics. Here are some of the highlights.
--PG&E is examining ways it can own its own solar thermal plants. Solar thermal plants--large, sprawling complexes that generate megawatts' worth of electricity from heat from the sun--are far more cost-effective than solar rooftop panels. "With solar farms, you can get down to 10 cents a kilowatt-hour," he said.
Technically, PG&E can build a solar thermal plant now, but it wouldn't qualify for the investment or production credits. That would put PG&E at a 30 percent cost disadvantage. Thus, if it can get that law changed, PG&E might build its own plant. Right now, the utility signs contracts to buy solar thermal-generated power from third-party companies like BrightSource Energy.
Why would it want to build and own solar plants? Solar thermal plants cost millions of dollars, and the start-ups trying to build them don't have the same capital as a major utility. A hiccup in the regulations or electricity demand could become a terminal setback for a start-up. PG&E could ride out such storms.
--He's not wild about a California ballot initiative to get 50 percent of the state's power from renewable sources. "There may be a time when 50 percent seems reasonable, but right now it seems too far out of reach," he said. Nonetheless, it could be possible to raise it from the current 20 percent level to 33 percent in the future. It depends on the state of renewables and the transmission grid.
--Nuclear power will likely make a comeback in the U.S., but the resurgence mostly might occur in the Southeast and other regions where renewables don't work as well. Besides, resistance among segments of California's population could make it difficult to build more nuclear plants there.
"Demand for power is so great in the U.S. that nuclear should play a role," he said.
--Plug-in hybrids could help promote wind power. A lot of wind power gets generated at night, but since few are awake to use it, it goes to waste. With plug-ins, that power could be used to recharge batteries. The utility is also working with Google and others on technology that would identify cars on the grid. With this, drivers could plug in their cars at work, and then sell power stored on their batteries back to the utility for peak prices. You'd buy at night when power is cheap and sell it in the day when it's expensive.
--He likes the idea of wave power, but building something that can survive the ocean won't be easy, "How do these technologies hold up in the Pacific when things get really nasty?" he posed. "What is clear is that you have constant motion in the ocean."
Correction: This story was corrected to reflect the day the briefing was held. It was Tuesday, April 30.
The renewable energy industry hits the fan Tuesday in California.
Pacific Gas & Electric and BioEnergy Solutions plans to open a pipeline Tuesday that will deliver methane to the utility from a manure-to-gas facility at a Fresno-area farm. Some farms in California, such as cheese maker Joseph Gallo Farms, and a number in Europe already generate gas from manure, but they also consume it to run their operations. This marks the first time that manure-generated gas will get sold across pipelines in the state.
BioEnergy Solutions owns and operates the digester (the thing that converts the manure into gas), which is located on the 5,000-cow farm, called Vintage Dairy. The company says it will soon build digesters at other nearby farms. The Vintage Dairy facility is expected to provide enough gas for 1,200 homes. Ultimately, BioEnergy will deliver 3 billion cubic feet of gas to PG&E a year, enough gas for 50,000 homes.
Although BioEnergy and PG&E talk about how many homes the gas could serve, the utility will actually use the gas to run electrical power plants. PG&E has set a goal of generating 20 percent of its
A single cow is probably good for 100 watts of power after the conversions are calculated, according to some estimates. Cows crank out about 120 pounds of manure a day. Just in case you were wondering.
PG&E wouldn't say what it is paying for the gas, but contends that the prices are competitive. Manure won't be the only source of renewable gas in the future. Other companies such as Ze-Gen and Onsite Power Systems are working on converting other types of trash into power.
BioEnergy uses the storage pond method for converting manure. In a nutshell, the manure is placed in a big pond with microbes, which break down the manure. The gas from the digester--which ordinarily would float into atmosphere and contribute to greenhouse gas levels--then goes to an upgrade facility that separates the methane from other gases conjured up by the manure. The digester will prevent approximately 1,500 tons of methane, one of the more harmful greenhouse gases, getting into the atmosphere from the Vintage farm alone.
The pond at the Vintage facility can hold around 37 million gallons of water and manure, which will no doubt make for great discussions on any Cub Scout field trip. Other companies, such as Microgy, have turned to thermophilic digesters, which use a combination of heat and microbes.
The gas from BioEnergy's Vintage digester will be piped to the nearby upgrade facility, which then connects to commercial natural gas pipelines. Other farms will also pipe gas to the facility.
Besides serving as a source for natural gas, these digesters serve other environmental functions. Manure storage facilities are a source of groundwater pollution as well as greenhouse gases, so the more that's digested, the better.
Normally, getting rid of manure is a regulatory and financial headache for farmers. With digesters, however, they typically no longer have to pay disposal fees, or can even get a small fee from the operator of the digester, depending on the contract.
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