Solar Power Colorado 2012: The potential for solar thermal

Here at Solar Power Colorado, solar thermal was referred to as the sleeping giant of renewable energy. That’s probably because, while solar PV efficiency currently tops out at about 20%, commercially available solar thermal efficiencies can be up to 80% efficient.

Solar thermal is a loose term for any device that uses the sun’s heat, rather than converting its energy into electricity, which accounts for its improved efficiency over PV. Solar thermal most often comes in the form of panels with a liquid underneath them. That liquid can then be used to heat water, the air inside a home, a pool, or even provide electricity and cooling when hooked up to a sterling engine, like the systems provided by Cool Energy.

In 2008, 28GW of solar thermal were installed worldwide, with China making up 78% of that. By contrast, the US had less than 1% of the market. Solar thermal systems are installed on more than 60 million homes in China and 10 million in European. In the US, fewer than 1 million homes have solar thermal of any kind. According to Tony Montgomery, Energy Organizer for the Colorado Environmental Coalition and co-Founder of the Solar Thermal Alliance of Colorado, “China is going full bore about developing every energy source they can. Many countries only have policies for solar thermal, while we have everything but.”

In 2010, there was about 5MW installed in the US. The Colorado Solar Thermal Alliance estimates that number could conservatively be 780MW by 2050. That means that it will be a $1 billion dollar industry, employing almost 25,000 people nationally by then. Of solar thermal costs, 2/3 are related to labor, meaning more money stays in the community where it is installed, a huge benefit for communities struggling in a tough economy.

Because solar thermal can run the gamut from simple, passive hot water heating to utility-scale concentrating solar power, one of the largest obstacles has been figuring out how solar thermal fits into existing renewable energy policy.

The EU, United Kingdom, and Canada are all making solar thermal an important part in their renewable energy plans for the future. The EU, for example, has the goal in place to generate 50% of heating requirements through solar thermal by 2050. That’s quite a lot for a continent with decidedly less sunshine than we get here.

Consistent policies and incentives are needed to allow us to catch up with the rest of the world. The problem becomes quantifying the energetic advantage of a solar thermal system. The renewable portfolio standard (RPS), arguably the most important policy driver for renewable energy, is based on electricity generation, so measures of electricity and fuel not used for heating are difficult to monetize. As a result, there is no impetus for utilities to encourage solar thermal because it reduces their business without contributing to their RPS requirements.

One approach would be to broaden demand-side management and efficiency incentives to include solar thermal. Another would be to create a second renewable portfolio standard, this one centered on Btu (British thermal units, the most common measure of heat), which could apply to biomass, geothermal, and solar thermal.

Currently, most homes are heated by natural gas, which has created an additional obstacle for solar thermal because it is so cheap and isn’t considered as dirty as other forms of carbon-based energy. Despite this, a solar thermal system can pay for itself in as little as 5 years because of its efficiency; a fact that hasn’t caught on with the public, yet. But, the members of the Solar Thermal Alliance of Colorado are confident that once policy catches up with technology and the public learns about its advantages, solar thermal is going to awaken and become a vital part of our energy portfolio.

Written by Sydney Kaufman, Contributing Editor, US, Solar Novus Today