Highest efficiency in solar electric power generation with advanced Stirling!

Independent tests by IT Power in the UK confirm that a single Ripasso dish can generate 75 to 85 megawatt hours of electricity a year - enough to power 24 typical UK homes. To make the same amount of electricity by burning coal would mean releasing roughly 81 metric tonnes of CO2 into the atmosphere.

Paul Gauche, director of the Solar Thermal Energy Research Group at the University of Stellenbosch has visited the test site many times. “The technology looks good to me. I’ve seen it working and I believe it meets the efficiency goals. The technology is proven with years of performance in the navy.”

He points out that it will be crucial to keep costs low enough to compete with photovoltaics, a significant challenge as their price falls every year. The system is also limited in that it is only useful in areas with consistent bright sunshine.

The technology works by using the mirrors as giant lenses that focus the sun’s energy to a tiny hot point, which in turn drives a zero-emission Stirling engine.

The Stirling engine was developed by Reverend Robert Stirling in Edinburgh in 1816 as an alternative to the steam engine. It uses alternate heating and cooling of an enclosed gas to drive pistons, which turn a flywheel. Because of the material limitations at the time, the advanced stirling engine that Ripasso uses was not commercially developed until 1988, when Swedish defence contractor Kokums started making them for submarines.

http://www.theguardian.com/environment/2015/may/13/could-this-be-the-worlds-most-efficient-solar-electricity-system

Greenhouse gas can be absorbed in soil, with organic soil management

What if there were a risk-free way of helping to mitigate climate change while simultaneously addressing food and water security?

A new report from the Center for Food Safety's Cool Foods Campaign says that such an opportunity is possible, and it's right below our feet.

Soil & Carbon: Soil Solutions to Climate Problems outlines how it is possible to take atmospheric CO2, which is fueling climate change, and plug it into the soil. Far from moving the problem from one place to another, this shift can reduce ocean acidification because the oceans are no longer the sink for vast amounts of CO2, and can regenerate degraded soils by providing needed carbon.

The report lays out the problem in this way:

Humans are altering the chemistry of where carbon is stored, and climate change is a manifestation of that alteration.

Another way of looking at the problem is that too much of the carbon that was once in a solid phase in the soil is now a gas. As a result, there is too much carbon in the atmosphere, too much in the ocean, but not enough stable carbon where it once was, in the soil.

The report adds that "cultivated soils globally have lost 50-70 percent of their original carbon content." Multiple factors have contributed to the problem, the report states: paving over land; converting grasslands to cropland; and agricultural practices that involve tillage and chemical inputs, which not only deprive soil of organic matter and rob it of the ability to store carbon but also contribute to flooding and erosion.

Regenerative practices like this help build healthy soil. (Photo: London Permaculture/flickr/cc)Healthy soils, in contrast, fed through organic agriculture practices, like polycultures, cover crops, and compost, give soil microbes the ability to store more CO2. Not only that, the report states, healthy soil can better weather both drought and floods because its structure allows it to act like a sponge. And healthy soil means better crop yields.

Just how much CO2 can be stored in soils is unclear, with one estimate cited in the report being 75-100 parts per million of CO.

But the bottom line, the report states, is that healthy soils will help communities have resilience in the face of climate change impacts.

The report concludes: "Unlike geoengineering, rebuilding soil carbon is a zero-risk, low-cost proposition. It has universal application, and we already know how to do it. All that stands in our way is a greater awareness of the opportunity and the political will to make it happen."

This story was originally published on Common Dreams.

Another strategy is to incorporate terra preta, charcoal, that remains active in the soil for thousands of years, and has been discovered in brazil in the amazon area, after all that time it still is active, absorbing carbon into the soil, and adding fertility all that time!