Monthly Archives: August 2015

OTEC

Temperaturunterschiede_OzeaneOtec_produkty-2_(English)

OTEC or Ocean Thermal Energy Conversion is a technology that has been around as a theoretical possibility since the late Nineteenth Century, and there have been a few prototype plants over the years. This week in Hawaii a small scale (50KW) plant opened. This is still more research and development than commercial scale operation but it is another step in the right direction.

I’ve blogged before about large scale marine source heat pumps. 3 weeks ago I wrote about Star Renewables and their project in Drammen Norway that is the major heat source for the town of 63,000 people, and in June 2014 I blogged about the National Trust installing a marine source heat pump at Plas Newydd in Anglesey. OTEC is in a way like a marine source heat pump, but utilizing the temperature difference between hot surface ocean waters and cold deep ocean waters to boil and chill a fluid such as ammonia with a very low boiling temperature, so generating stream and driving a turbine to produce electricity. As the diagram above shows OTEC has, at least in theory, many possible spin off uses that could be very beneficial.

OTEC works best where there is the greatest temperature difference between hot surface water and cold deep ocean water, and as the map above shows it is in the Pacific Ocean roughly between Japan and Hawaii that this technology will work best. Perhaps, unsurprisingly, the two leading research centres for this technology have been in Japan and Hawaii, and both have prioritised renewables as a major part of their energy economies. Makai Ocean Engineering built the new Hawaii plant, do check-out their website where there’s a good video explaining the technology.

http://www.makai.com/ocean-thermal-energy-conversion/

https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion

Buses & Trams

World's first Hydrogen Fuel Cell Tram

World’s first Hydrogen Fuel Cell Tram

Modern cities need good public transport systems. As diesel buses are responsible for much air pollution they’ll need to be replaced with cleaner technologies. London has long had an electric underground, and many cities have electric trolley buses, using overhead power lines. Some British cities are building electric tram lines, emulating their European counterparts. Other options are now emerging as both hydrogen fuel cell and electric battery technologies are improving.

London has about 8,700 buses, mainly still diesel. These are increasingly being retrofitted to reduce nitrogen oxide emissions. Diesel electric hybrids are increasingly common, and perhaps a dozen or so all electric single decker buses now operate in the city. In October London is due to get its first all electric double-decker bus, looking very like a Routemaster; it is being built in China by BYD. China is the world leader in battery electric bus manufacture and deployment. Various Chinese cities are forging ahead with a range of zero tailpipe emission transportation systems.

For many years there had been talk of a hydrogen fuel cell revolution, and now slowly it’s beginning to take shape. The photo above is of the world’s first hydrogen fuel cell tram, built in Qingdao, China, by Qingdao Sifang.

China has very impressive plans to roll out zero emission transport systems to many of its cities. Hydrogen fuel cell trams, ordinary electric trams and battery electric buses are all set to become common sights across China in the next few years. As this is achieved the air quality in Chinese cities should rapidly improve. At the same time investments in renewable energy technology, and in energy efficiency, should ensure that the worst coal power stations can be closed, and at last the upward climb of Chinese carbon emissions can be halted, and hopefully reversed.

Electric buses http://www.theguardian.com/environment/2015/jul/18/chinese-built-zero-emissions-electric-bus-prepares-for-service-in-london and http://www.sonnenseite.com/en/mobility/electric-buses-more-billion-dollar-orders.html

Hydrogen tram http://www.bloomberg.com/news/articles/2015-03-25/china-s-hydrogen-powered-future-starts-in-trams-not-cars