Sunday, October 21, 2018

Home Biogas How to get energy from Trash - Chinese Home Digester Design

This is our version of the basic information on buried Chinese home biogas plant designs, as provided very expertly on the Eco Tipping website.

Why Eco Tipping? We assume this was features on the Eco Tipping website because if everyone was to adopt home biogas as an energy source the fate of planet earth would be tipped toward being sustainable.
The following is the part of the original article which we have used to make the above video:
The basic biogas system involves an anaerobic digester (usually underground) with an inlet pipe, an outlet pipe, and a tube for the biogas.
The feedstock is a combination of plant and animal wastes, plus water. Crop residues as well as tree litter and weeds are suitable, as are manure from pigs, cows, chickens, and humans.
It ferments in the digester tank to produce biogas, which contains 60-70% methane (CH4).
The energy content is 22 gigajoules (GJ=1 billion joules) per m3, about the same as 0.5 liter of kerosene.
The basic chemical reaction is: 2 C + 2 H2O » CH4  + CO2. The process occurs with the aid of bacteria, and is temperature sensitive (range is 8-60° C).
Under ideal conditions, a 10 m3 digester can supply enough gas for cooking and lighting for a family of five. Biogas can also be used for fueling farm machinery and for power generation.
Both the liquid sludge from the outlet pipe and the sediment at the bottom of the tank are very good fertilizers. via EcoTipping

The following are our views on Home Biogas Plants:

Home biogas is widely produced in developing regions of the world. It has been used in the greatest numbers in rural China where exceeding 30 million of thse plants ahve been built.

Home biogas basics Chinese anaerobic digestion plant buried digester design information.
Unfortunately, the design relies entirely on the skill of local builders to make these plants gas-tight. Doign that is not easy, and leaks may occur after backfilling the tanks when repairs would be very difficult.

There is also no way to test this design of home biogas plant before it is filled with digestate. Many of thse plants lie unused due to such difficulties.

Thta's why designs using purpose built tanks above ground are much better, as long as they are ewll insulated from cold climates, and can be kept warm for efficient biogas production.

Israeli startup Home Biogas has developed a relatively affordable home-sized biogas unit that allows people to convert their own waste into fuel.

In Israel, where temperatures get quite hot in summer but where winter lows have included snowfall, the start-up company Eco-gas Home Biogas has launched commercial biodigesters for the home and small institution.

Many people say that to make your own home energy the alternative method of usign solar panels is better. We do not agree. Solar panels are expensive and the high initial costs takes perhaps 10 year to repay in energy cost savings. The initial cost of a home biogas plant is lower than a solar array. In addition to the lower upfront cost, home biogas does not require a grid-tie or any type of energy storage, as energy is stored in gas form and used on-demand when needed.

Friday, October 05, 2018

The Food for Fuel Debate and Biogas

Food versus Fuel Facts About Biogas Energy

There is no doubt that until recently there was a powerful concern that in nations such as the US, parts of South America, and the EU (especially in Germany), renewable biofuel production would reduce food available to eat.

The result would be rising food prices for us all.

For a while, governments were so keen to encourage renewable fuels, to reduce climate-changing emissions that they seemed to forget that people must come first when food is needed.

Some were saying things like:

"Crops Used for AD raise the price of food", and that "People could go hungry as a result".

But, this was not primarily aimed at biogas production.

The technology used for the original diesel-fuel-replacement biofuels, which were widely subsidized was, and still is, the chemical conversion of vegetable oils into bio-diesel.

This is a diesel fuel replacement which is added to the fuel bought at filling stations, and lots of it is still produced.

The production of biogas using the anaerobic digestion process is a completely different process.

AD processes once received subsidies for crops such as maize and beet as well as agricultural biomass waste and, in parts of the EU.

As a result of the spin-off from the main biodiesel "Food-for-Fuel" debate, such subsidies have all-but ceased. They are now historical and are no longer granted.

Unfortunately, anaerobic digestion and biogas has become erroneously tarred with the same "Food versus Fuel" brush. This is wrong in our opinion.

Image illustrates the food for fuel biogas debate.

When crops are grown for AD, this is usually done as part of a traditional agricultural rotation, helping farmers to improve food crop yields and soil quality, or these are grown on marginal land not suitable for food crops.

The amount of land used for growing crops for energy generation in England is less than 1%. This figure is even lower across the devolved nations of the UK. More land is used for golf courses.

The ADBA analysis also shows that the growing of these crops has had no discernible impact on food supply for humans or livestock.

The following are just some of the reasons to support the agricultural production of biogas fuel, when based upon using crop and other waste.

AD has a vital role to play in recycling wastes, reducing greenhouse gas emissions, and producing the renewable energy, clean transport fuel, and soil-restoring biofertiliser that the UK desperately needs.

Source: AD and Bioresources News Issue 41, Autumn 2018

For another article about biogas myths including food for fuel subsidies visit here.