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Wednesday, November 18, 2020

Can CCS and CCUS lead us to achieve Net Zero emission by 2050?

 CCS (carbon capture and sequestration) and CCUS (Carbon capture, utilization, and storage) technologies are essentially “after thought” to fix the CO2 emission by 2050. It also indirectly encourages continuity of fossil fuel usage for a foreseeable future to help those industries who have invested billions of dollars in creating their infrastructures such as “fracking”. Fracking generates hundreds of cubic meters of toxic effluent whose salinity is more than ten times that of the salinity of seawater.  It is an environmental nightmare. Are these technologies practicable? Will they pay $100 or more for a ton of CO2 to capture and then transport hundreds of kms distance to find a suitable site; and even if they pay what will be the cost implications? Certainly, their cost of production will sharply increase, which will be necessarily passed on to the consumers whether it is a power industry or oil and gas industry. Why some of the CCS projects are dormant in many parts of the world? They claim injecting CO2 into existing oil field will increase oil production. Is there an evidence to substantiate such claims? But how many such oil fields exist in Australia, for example? The same question should be raised for all the countries around the world especially those oil importing countries like India, for example.  IEA should publish necessary data to back up they claim that CCS and CCUS will lead to zero emission by 2050. In the absence of such data and hard evidence and the cost and economic analysis these projects will lead us nowhere? Without imposing Carbon tax as a financial incentive (not as a penalty) will these industries embark upon such a venture? The Carbon tax cannot be less than $250/Mt (because Carbon capture from air, for example, cost more than $150 to 200/Mt depending upon the maturity of technology). Now they want to utilize capture Carbon to produce synthetic fuel with green Hydrogen. Green hydrogen is awfully expensive, renewable energy is costly and storing them is prohibitively costly and converting them to Hydrogen by electrolysis is even more expensive. Despite all these expensive measures can zero emission be achieved by 2050. The cost of green fuel will be 10 times more than fossil fuels currently used. Will consumers afford to pay for such high fuel cos? Many questions remain unanswered. The word “Carbon capture” implies continuity of fossil fuel. It is like tobacco industry. At least in cigarette packs there is a warning ” smoking is injuries to health” but there is no such warnings in CCS or CCUS because the “captured CO2 will be released into atmosphere slowly at the point of usage in the near future , for example, Urea made out of captured CO2 will slowly release CO2 back into atmosphere by soli enzymes. Conversion to “concrete” or “nano Carbon” are claimed to be potential products but only future can tell. We are talking about “billions of tons of CO2”. Only carbon recycling and circular economy will be the answer and not CCS or CCUS.

Sunday, March 29, 2020

Renewable synthetic methane gas (RSMG) and Ramana Power Cycle (RPC) for Zero emission base load power.

RSMG is an abbreviation for ‘Renewable synthetic methane gas’ and it is a new form of a Carbon negative synthetic fuel to substitute natural gas. It is synthesized using  CO2 extracted from the sea or from power plant using Oxy combustion CO2 power cycle at the site such as CES, Graz cycle or Allam cycle (using supercritical CO2 as working fluid)  and Renewable Hydrogen (RH) by the following reactions using a renewable energy source.
1.    CO2=> CO + ½ O2 (electro-chemical reduction)
2.    CO + 3 H2=> CH4 + H2O (catalytic conversion)
There are other methods too can be applied but our patented process uses a unique method to synthesize RSMG from CO2 and renewable Hydrogen with a heating value (LHV) around 52 Mj/kg.
By using only, the sun and sea water, RSMG is continuously synthesized using continuous renewable energy such as OTE (ocean thermal energy) on 24 x 7 basis. Ocean is the largest reservoir for clean drinking water, Carbon dioxide, Hydrogen and thermal energy and it is imperative that the absorbed CO2 is extracted along with  stored thermal energy in order to restore the warming ocean to pre-industrial state to mitigate climate change. The success of the system depends on the availability of the lowest cost of renewable energy on 24 x7 basis such as Hydro or OTEC. Alternatively, the cost of renewable energy should be less than a $0.05/kwh.
What is RSMG?
RSMG is like natural gas with higher heating value consisting of pure methane and Hydrogen with no other impurities such as sulfur compounds or CO2. It is synthesized using a proprietary technology using CO2 extracted from seawater and renewable hydrogen (RH) using a renewable energy sources such as OTEC or Solar/wind etc. It can be compressed like CNG or liquified like LNG and can be transported or shipped to various destinations. RSMG is a Carbon negative fuel because it uses already absorbed CO2 from the sea and not from burning fossil fuel and it is also renewable because the O2 from CO2 emission is substituted with renewable Hydrogen (RH) constituting synthetic CH4. The purpose of this technology is to recycle Carbon indefinitely at the site of usage and that is why transportation in the form of CNG or LNG is discouraged.

Ramana Power Cycle (RPC)
RPC is a new patent (pending) technology to generate a base load power 24 x7 using a renewable synthetic methane gas (RSMG) with Zero emission. By constantly recycling CO2 in the form of RSMG during Oxy combustion CO2 power cycle we can eliminate usage of fossil fuel completely. Moreover, there will be no need to extract further CO2 from seawater for a specific power plant because Carbon is being recycled constantly. Only further RH will be required to run the base load power plant.
How RPC works?
RPC uses an Oxy combustion power cycle such as CES, Graz cycle or Allam cycle (using super critical CO2 as a working fluid) to generate a base load 24 x7 power. It uses 80% of CO2 generated internally leaving 20% high purity pipeline grade CO2 which is used to synthesize RSMG at site for recycling. That is why RSMG is renewable. Thus, RPC continues to generate a base load power with Zero emission. The electric efficiency of RPC is nearly 70 % and the cost of power is competitive to any other power source. By continuously generating RSMG and recycling CO2 it achieves Zero emission without any requirement of fossil fuel such as natural gas. Thus, the process can decarbonize the fossil fuel industry completely at the fastest time frame. Using 100% renewable hydrogen (RH) in gas turbine is still a long way off to achieve a commercial reality. Currently only up to 30% RH has been tested along natural gas (30:70) and there are several technical problems to be solved with combustor. Moreover, the maximum efficiency in Hydrogen based gas turbine will not exceed 35% at the maximum.

How RPC is different from Allam cycle, for example?
Allam cycle has been selected by IEA (International energy agency) as the most efficient (electric efficiency at 55.4%) Oxy combustion power cycle to generate a base load power using natural gas. It generates 20% pipeline grade CO2 as by-product suitable for CCS applications. It requires natural gas as a fuel. It generates pure Oxygen from air using ASU (air separation unit) by cryogenic process. Air separation is an energy intensive process consuming as much as 15% generated power internally thereby reducing overall electric efficiency of the system. Moreover 20% CO2 discharged from the plant requires long distance piping and sequestration both are expensive thus increasing the cost of power.
RPC uses pure Oxygen generated as by-product of renewable hydrogen (RH) by electrolysis for Oxy combustion of RSMG and to continue to generate a base load power at highest electrical efficiency at competitive rate. Synthesis of RSMG is highly exothermic chemical reaction which generates superheated steam as a by-product which generates additional power using steam turbine thus enhancing the overall electric efficiency of RPC.
RPC is suitable only for large power generation such as 100 Mw and above. The process requires the cheapest and continuous renewable energy source such as OTEC, offshore wind turbines supplemented by PV solar. The main advantage of the system is it does not require large scale energy storage and the base load power can be exported directly to the grid using a substation as it has been done over several decades.
RPC has the potential to decarbonize the fossil economy at the fastest rate than any other methods currently used.
Any power generation technology should be able to meet the following seven criteria in order to be successful.
1.Power availability.
2.Power dispatchability.
3.Zero emissions.
4.Lowest levelized cost of power
5.Potential to decarbonize the fossil economy at the shortest time frame.
6.Potential to Completely eliminate fossil fuel
7. Sustainable and has a potential to achieve circular economy.
RPC can meet all the above seven criteria.