solar electricity

Old Windmill (image by waterwin, CC 2.0 license)

The results of this study on solutions to global warming, air pollution, and energy security, by Stanford professor Mark Z. Jacobson, are somewhat surprising, given the drumbeat from many areas on both nuclear and biofuels as necessary for the salvation of the world.

Jacobson analyzes 12 energy sources for their beneficial impact on global warming, air pollution, and energy security - the ten electricity sources are solar-photovoltaics (PV), concentrated solar power (CSP), wind, geothermal, hydroelectric, wave, tidal, nuclear, and coal with carbon capture and storage (CCS) technology; the two liquid fuel options are corn-ethanol (E85) and cellulosic-E85.

An article in Science Daily summarizes one of Jacobson’s conclusions:

Jacobson said that while some people are under the impression that wind and wave power are too variable to provide steady amounts of electricity, his research group has already shown in previous research that by properly coordinating the energy output from wind farms in different locations, the potential problem with variability can be overcome and a steady supply of baseline power delivered to users.

As the bottom line in the study, Jacobson writes:

In summary, the use of wind, CSP, geothermal, tidal, solar, wave, and hydroelectric to provide electricity for BEVs [battery electric vehicles] and HFCVs [hydrogen fuel cell vehicles] result in the most benefit and least impact among the options considered. Coal-CCS and nuclear provide less benefit with greater negative impacts. The biofuel options provide no certain benefit and result in significant negative impacts. Because sufficient clean natural resources (e.g., wind, sunlight, hot water, ocean energy, gravitational energy) exists to power all energy for the world, the results here suggest that the diversion of attention to the less efficient or non-efficient options represents an opportunity cost that delays solutions to climate and air pollution health problems.

Note that the study ranks the various energy alternatives without regard to cost. That’s going to be controversial. Jacobson says:

Costs are not examined since policy decisions should be based on the ability of a technology to address a problem rather than costs (e.g., the U.S. Clean Air Act Amendments of 1970 prohibit the use of cost as a basis for determining regulations required to meet air pollution standards) and because costs of new technologies will change over time, particularly as they are used on a large scale.

In the real world, costs do have a major impact, especially given that we do not have a Clean Air Act regarding carbon today. This is why it’s so important that the price/kW of solar panels, for example, is dropping and will continue to drop.

In fact, when you leave cost out of the equation, is it surprising which energy sources came out on top? Let me know your thoughts.

Solar Power International Logo

The opening keynotes at the Solar Power International trade show last week were eye-opening. (See the Tuesday Keynotes video on this page - Resch at 20 minutes, Hamm at 37 minutes.)

Rhone Resch of the Solar Energy Industries Association first told the story of getting the investment tax credit for solar renewed - 17 failed votes before it finally passed with the Paulson Bailout bill. He then outlined the benefits to the solar industry of the ITC - stability for solar energy businesses, creation of thousands of new business opportunities due to the remove of the residential solar cap, and a return to leadership of the US in solar. “Solar energy is going to create 440k new jobs, 1.2 million new solar installations, and 28 gigawatts of new capacity - enough to power seven million homes throughout the U.S.”

To achieve the 28 gigawatts of new solar electric generation capacity predicted by Resch in the next eight years, Julia Hamm of the Solar Electric Power Association (SEPA) threw down a challenge to the attendees. The industry must “be bold, be innovative, be strategic.” In particular, she outlined four key policy guidelines the industry must embrace to achieve this goal.

Utility Ownership of Solar Power Projects

The utility and solar industries must collaborate to find program structures, such as utility ownership of distributed photovoltaics, that provide a winning scenario for both industries, as well as for customers at large. The solar industry can utilize this new market segment as a buffer until home and small business owners are back on more solid financial footing.

Increased Utility Engagement in Solar Markets

The utility and solar industries must work together to get more utilities engaged, starting by increasing the solar knowledge base of utility employees, from top executives down to distribution engineers. We must move beyond having ninety seven percent of all grid-connected solar installations in just 10 utilities’ service territories.

Greased Wheels

The utility and solar industries must work in partnership with regulators and investors to push for approval and funding of new transmission projects and the development of smart grid configurations to expedite the timeframe in which new utility-scale and distributed solar projects can come on line and provide maximum value.

Development of Innovative Approaches

By working in collaboration, the utility and solar industries can make great strides towards modernizing today’s electricity infrastructure and offering customers affordable and clean power. But the status quo will not cut it. We need bold new ideas developed in tandem for the mutual benefit of both industries, and society at large.

(A press release version of this challenge is here.)

The 28 gigawatt figure represents an increase in solar capacity of more than thirty fold between 2009 and 2016. This is approximately three times the estimated amount of generation predicted to come online as a result of existing renewable portfolio standards and policies in states with existing solar carve outs.

However, not only does 30-fold growth far outstrip most predictions for solar energy capacity in the next eight years, it has another interesting property. It corresponds to a “Moore’s Law-type” of growth, with a doubling period of about every 18 months. This is the first time I’ve heard a solar energy organization step up to a prediction of a Moore’s Law-type growth rate. And it means that in 18 years, if the doubling rate stays constant, solar would be responsible for over 400 gigawatts of capacity, or just about equal to our current energy usage in the U.S. Solar could be providing nearly 100 percent of our energy by 2026, or even more if our overall energy usage goes down due to efficiency, as is possible given California’s example.

And if our solar capacity keeps on doubling every year and half after that? What will we do with all that energy? Your comments welcome, of course!

Mission Peak in Fremont, CA. Image via Wikipedia

A roundup of a few stories that came out this week that I found particularly interesting.

• Solyndra, a startup in Fremont, CA (just down the street from my office), is using a new form factor for thin film solar cells:
  

  Unlike conventional solar panels, which are made of flat solar cells, the new panels comprise rows of cylindrical solar cells made of a thin film of semiconductor material. The material is made of copper, indium, gallium, and selenium. To make the cells, the company deposits the semiconductor material on a glass tube. That’s then encapsulated within another glass tube with electrical connections that resemble those on fluorescent lightbulbs. The new shape allows the system to absorb more light over the course of a day than conventional solar panels do, and therefore generate more power.

  Not only do they not need trackers, but because they are mounted with space between each tube, they aren’t susceptible to wind and they can collect light reflected off the building’s roof and ambient light coming in obliquely.

  What I like about this story is that it shows that there’s still a lot more innovation to be done in all areas of alternative energy design - yesterday I saw another report about a new fuel cell membrane made of a cheap material instead of platinum, and there’s practically a new wind energy device every week. They’re not all going to be winners, but it’s the kind of design ferment that’s going to lead to big cost and practicality improvements in every area.

• The EPA provides an interactive analysis (using Google Earth) of marginal and contaminated land that could be used for renewable energy farms - wind and/or solar:
  

  According to the EPA, many lands tracked by the agency, such as large Superfund sites, and mining sites offer thousands of acres of land, and may be situated in areas where the presence of wind and solar structures are less likely to be met with aesthetic, and therefore political, opposition.

  One stumbling block for a massive transition to solar power in the U.S. has been the land use question. I’m not saying we want to build our power on contaminated lands, but it’s interesting to see this as an option.

  Via CleanTechnica.com

• Renault commits to electric vehicles. Saying that:
  

  “EVs are a necessity because hybrids cannot deliver the level of gasoline use and emissions reductions that governments and customers are demanding of automakers”

  Renault unveiled two zero-emission concept cars at the Paris autoshow Mondiale de l’Automobile, both of which are pure electric. The cars have a range of 160-200 kilometers (95-120 miles) and are designed for day-to-day use and short weekend trips, “not vacations” as Renault admits.

  Renault is committing to EVs because they believe that’s the only they’ll be able to deliver the gasoline economy and emissions reductions being demanded by both the market and governments.

These stories caught my eye as not just “more of the same” this week. What green energy stories got your interest up recently?

Solar power systems covering the areas defined by the dark disks could provide more than the world total primary energy demand in 2006 (assuming a conversion efficiency of 8%). Image from Wikipedia.

I recently asked physicist Richard Muller whether he thought the price-performance of solar electricity generation would follow a Moore’s Law-type curve. He said that this would not occur due to improving the efficiency of solar collection, as the current levels of efficiency - 20-40% - are reasonably high. However, he added

“I do expect the price to drop by a factor of 10, so we will have lots of solar.”

Well, in the nature of things, there’s definitely a limit to how much energy a solar PV collector can get from a square meter of sunlight. (There’s about 1kw of energy in a square meter - as I learned in Physics For Future Presidents, by Professor Muller - so we can expect to get 400 watts or less.) The amount of this energy per square meter we can collect will go up, but asymptotically approach (at best) the physical limits.

On the other hand, I’d argue that the cost of collecting it can go down a nearly unlimited amount - certainly multiple orders of magnitude. So what will solar PV look like in 2018 - ten years from now?

Read the rest of this entry »

A laundromat in California with rooftop solar collectors (Image via Wikipedia)

As we contemplate the future of energy, and the combination of utility-level and distributed energy, and of different types - solar PV, solar thermal (heat your own hot water for showers), wind, etc., one question I have asked myself is how much energy can realistically be produced by the solar collectors on the roofs of our houses and office buildings in the U.S.?

It turns out the United States government has done some research on this! There’s a very interesting set of Department Of Energy reports, including one (PDF) on the market opportunities for grid-tied distributed solar PV. It figures out, state by state, how much roof surface is available, how attractive the incentives and infrastructure are (e.g., is there net metering?) and uses some simple algorithms to come up with an expected market penetration for solar PV on commercial and residential roofs. The resulting amount of electricity generated in this distributed fashion is amazingly high. Their best case scenario has installed MWs of rooftop solar PVs rising from about 2,000 in 2008 to almost 25,000 in 2015, more than a factor of ten increase over seven years.

Influence of system pricing, net metering policy, federal tax credits, and interconnection policy on cumulative installations

The report uses conservative numbers for solar PV cost improvements - breakthoughs and innovations like the ones mentioned in Technology Review every week (like this one), will make the market penetration even faster (and higher) as they come to market.

I was pleased to see that our government has done this kind of research. Think what could be done if funding for renewable energy research and development was an order of magnitude higher!